Re: (ITS#7775) LMDB terminates Postfix daemon process without logfile record

[wietse@porcupine.org]

Wietse Venema:
> > env can be NULL. mdb_env_set_assert(env,cb) also sets a static
> > variable with the callback for the asserts which do not know of an
> > env.  Could throw away that part later.  Currently it only applies
> > to one assert().
> > 
> > The branch also invalidates a transaction on any page allocation
> > error, since the callers do not always clean up afterwards.  Too
> > aggressive, can be reverted after updating the callers. But for
> > now it means MDB_MAP_FULL & co won't let the user commit an
> > inconsistent transaction.
> 
> Thanks, this is more improvement than I asked for. I don't want to
> slip my schedule, and to avoid last-minute surprises, I will postpone
> the review and impact test of these improvements after the stable
> Postfix release 2-3 weeks from today.

It looks like you are switching from a stop-gap fix (bare-bones
call-back) to a more permanent solution.

In that case I must mention again that I need to register not only
a call-back function pointer but also a void* pointer that is
returned to me at call-back time.

Getting the MDB_env at call-back time does not help me at all,
because my programs open many databases (including non-LMDB).

To find out which database is affected I need my own pointer to my
own (DICT) object that encapsulates the LMDB database.  Then I can
decide if the problem is with a disposable cache. in which case the
program can continue with degraded performance.

	Wietse